Distichiasis, or two rows of eyelashes, is sometimes confused with districhiasis (three rows of lashes) or trichiasis.  True distichiasis often occurs in all four lids and is sometimes associated with other lid anomalies such as ptosis, trichiasis, corneal damage, congenital ectropion and absence of Meibomian glands.  It has occasionally been found only in the lower lids and much more rarely just in the upper lids. In distichiasis, the second row of lashes emerges from the orifices of the Meibomian glands which distinguishes it from acquired trichiasis in which the normally placed lashes are misdirected.  The abnormal lashes are usually thinner, shorter, and less pigmented than the normal lashes.  They number from 3-20 with an average of 12-15.